jD91mZM2
51 lines
1.4 KiB
C
51 lines
1.4 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <sys/mman.h>
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#include <unistd.h>
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#include "test_helpers.h"
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int main() {
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int page_size = getpagesize();
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printf("Page size: %d\n", page_size);
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puts("Mapping 1 page of memory...");
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char *map1 = mmap((void *) 0x200000000, (size_t) page_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED_NOREPLACE, -1, 0);
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puts("Mapping 3 pages of memory...");
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char *map2 = mmap(map1 + page_size, (size_t) page_size * 3, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED_NOREPLACE, -1, 0);
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ERROR_IF(mmap, map1, == MAP_FAILED);
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ERROR_IF(mmap, map2, == MAP_FAILED);
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puts("Randomizing mapping #1");
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for (int i = 0; i < page_size; ++i) {
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map1[i] = (char) (rand() & 0xFF);
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}
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puts("Randomizing mapping #2");
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for (int i = 0; i < page_size * 3; ++i) {
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map2[i] = (char) (rand() & 0xFF);
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}
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puts("Unmapping page 2 of map2");
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munmap(map2 + page_size, page_size);
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puts("Randomizing page 1 of mapping #2");
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for (int i = 0; i < page_size; ++i) {
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map2[i] = (char) (rand() % 256);
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}
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puts("Randomizing page 3 of mapping #2");
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for (int i = 0; i < page_size; ++i) {
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map2[page_size * 2 + i] = (char) (rand() % 256);
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}
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// Page fault:
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// map2[page_size] = 0;
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puts("Unmapping it all at once!");
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munmap(map1, (size_t) page_size * 4);
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// Page fault:
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// *map2 = 0;
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}
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